I have a Encore 5.1 Sound card and have installed it. My problem is that I don't get a normal sound input when I bring in the output of my cassette player into any of three ports I have in my pc, front,...
When you install the sound card drivers, they disable ALL motherboard sound functions, and enable them on the sound card, meaning you can do the same things, with better quality, you just need to connect everything to the soundcard or it won't work. SO then you cannot connect any sound to the front of the computer anymore, but a soundcard should have plenty of connections on the back side of the PC.
From what I understood from your story, you switched cassette players AND installed a sound card. If I were you I'd first install the sound card drivers, then try to play audio with the old cassette player, and see wether that works. If it does, your new cassette player has another (if at all) output than the old one. Then you'll just have to use the old one. If it does not work, your soundcard is the problem, which seems a bit odd. Soundcards are usually meant to do more than on-board sound, not less. I'd contact your manufacturer and ask wether it's normal this doesn't work, or that the card's broken.
I hope this helps,